It is well known that collated books are often bound using a helical coil which passes through aligned holes at one edge of the book. This provides a book which can be easily opened and held at an opened position and is therefore particularly effective for manuals and reference materials.
The helical coil at the edge of the book can be formed from a coiled wire or a coiled strip of plastic material. The coiled wire has the significant advantage that it can be more easily inserted. The helical plastic coil has the advantages that it can be manufactured in different colours and therefore provides a particularly attractive appearance as opposed to the strictly utilitarian appearance of the steel wire.
The major disadvantage of the plastic coil is that it is necessarily thicker and the surface is more resistant to insertion into the aligned holes at the edge of the book so that the plastic coil is significantly more difficult to insert.
This difficulty in insertion has led firstly to an inability to automate the process so that it is normally carried out by hand. Secondly, this difficulty in insertion has led to resistance by the trade binderies to the use of plastic coil due to the difficulty in finding effective skilled labour that can carry out the insertion at a reasonable cost.
Up until now, therefore, there has been no effective commercial machine which provides automation of the insertion process.